SMTP 5.7.1 Error when sending an email, What does it mean?
SMTP 5.7.1 Error message indicates the recipient may have mailbox restrictions which mean the delivery of your email is not permitted.
Prolateral Consulting Ltd
Bramingham Business Centre, Enterprise Way, Luton, Bedfordshire, LU3
VAT No. GB 814 3886 16 | Company Reg No. 4676923